Well, sure. But it is not like Hickey invented the 5bit partitioned trie (there is work in sml and Haskell before that), nor did he invent functional tries.

He took what was a research topic and made it standard. There were no other 5bit partitioned tries in (wide) use. I think he did that in a way that signals a fantastic sense of taste, and if you are implementing a programming language you need taste.